Grinding mill



2 Sheets-Sheet 1.

(No Model.)

W. D. GRAY.

GRINDING MILL.

8 7 oo 1 w 3 t 4 LLU N. PETERS. PhntuLflhagraphzr. WnsNngwm D. Q

(No Model.) 2 Sheezssheec 2. W. D. GRAY.

GRINDING MILL.

No. 388,968. Patented Sept. 4, 1888.

NVILLIAM D. GRAY, OF MIL'WAUKEE, VlSOONSIN, ASSIGNOR TO E. P. ALLIS 8E (10., OF SAME PLACE.

GRINDING-NULL.

SPECIPICATIQN forming part of Letters Patent No. 388,968, dated September a, 1888.

Serial No. 138,780.

(No modem To all whom, it may concern.-

Be it known that I, WILLIAM D. GRAY, of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented a certain new and useful Improvement in Grinding Mills, of which the following is a full, clear, and exact specification.

This invention relates to those grindingmills in which provision is made for throwing the cooperating rolls apart at will to stop the grinding action, and in which the delivery of the material to the grinding-rolls is controlled by an adjustable gate connected by intermediate devices with the roll-spreading mechanism, so that the adjustment of the gate and the rolls is effected at one operation.

As the mills are usually adjusted, the movement of the gate and the rolls is effected simultaneously. My improvements relate toa mechanism whereby the feed-gates are first closed and the grindingrolls subsequently separated at one operation, the rolls being thus permitted to reduce the material already delivered upon them before they are separated.

It also relates to a construction and arrangement of mechanism whereby the opening of the gates is effected previous to the closing of the rolls, so that there will be no danger of the rolls running in contact with each other.

M y improvement is applicable alike to mills having a single pair of rolls and to those having two pairs of rolls, which are commonly denominated double roller mills. I have shrilwn the invention applied to both forms of mi As the invention is susceptible of modification in the form of its embodiment, I have also represented in the drawings certain of these changes.

In the accompanying drawings, Figure 1 represents a side elevation of a double-roller mill having my improvementincorporated therein, the side of the hopper being broken away to expose the internal feedgates. Fig. 2 is a side elevation of another double mill having my improvement applied thereto in a form somewhat different from that in the preceding fig ure. Fig. 3 is a crossscction on the line a: w of Fig. 1. Fig. 4 is a. side elevation of a sin gie mill provided with devices similar to those shown in Fig. 1, a portion of the feedroll and hopper being shown in section. Fig. 5 is an elevation, partly in section, showing another form of my mechanism. Fig. 6 is a cross-section on the line 3/ y of Fig. 5. Fig. 7 is a sectional view illustrating a modified form of the parts shown in Fig. (5. Fig. 8 is an elevation, partly in section, of one side of the feed-hopper, the feed-roll, the feed-gate, and attendant part-s.

Referring to Fig. 1, A represents the base or frame of the mill; B B, two grinding-rolls in fixed bearings therein; C O, thegrindingrolls mounted in the upper ends of arms D, which are pivoted at or near the middle to their frame. Attheir lower ends these arms are connected to 'rods E, which are extended inward to the middle of the frame and mounted at their inner ends upon and around eccentrics F on a rockshaft, G, passing through the frame from side to side, the rotation of this shaft serving through the eccentrics, rods, and roll-supporting arms to throw the two movable rolls simultaneously toward or away from the fixed rolls. These parts constitute what is commonly known as the roll spreading mechanism, and are not separately claimed herein.

The rock-shaft is provided at one end with a crank-arm, H, pivoted to a pitman, Lwhich extends upward to one end of an angular handlever, J, pivoted on the side of the main frame, the lever serving through the intermediate parts to effect the spreading of the rolls. The pitman, instead of being pivoted to the handlever, is slotted at its upper end to receive a stud on the lever, whereby a limited amount of play or lost motion is allowed between the lever and pitman, for a purpose which will presently appear. At its top the mill is pro vided with the usual feed-hopper, K, having at its lower side two throats, through which the material passes to the respective pairs of grinding-rolls. Beneath each throatis a horizontal feed-roll, L, which may receive motion in any ordinary or suitable manner, the present invention having no relation thereto.

Over each feed-roll I mount a vertically swinging or revolving gate, S, in the form of a segment of a hollow cylinder, provided at the ends with ears, through each of which apivoted bolt or pin, a, is extended. The outer surface of the gate is concentric with the pivot and is fitted closely against the inner surface of the hopper to maintain a tight joint and prevent the escape of material, except as it may pass between the lower edge of the gate and the upper surface of the feed-roll. Each gate is provided with an upright arm, b. The

arms of the two gates are connected by rods 0 to opposite ends ofa cross-bar or double crank, d, located at the side and upon thejournal or pivot of the hand-lever J.

Between the hand lever and the cross bar or lever dis a frictional plate or washer, f, which transmits motion from the hand-lever t0 the cross-bar and gates,at the same time permitting the lever to continue its movementin either direction afterthe motion of the gates and their connection is arrested. The upward opening movement of each gate is limited by a stoppin, g, applied. to the hopper, as in Fig. 4., while their downward movement is limited by their contact with the feed rolls or otherwise, as may be desired.

The operation of the parts is as follows: Assume that the parts stand in the position shown in Fig. 1, with the grinding-rolls separated and the feed gates closed. At this time the stud on the hand-lever will stand in the lower end of the slot of the roll-controlling pitman I. On moving the hand'lever to the right, motion is communicated therefrom through the frictional plate or washer to the lever d, and thence to the two.feed-gates,which are caused to open. At or about the instant that the feed-gates reach their limit of movement the stud on the hand-lever encounters the upper end of the slot in the pitman I, whereupon, the motion of the lever being continued, the pitman is elevated and caused through the intermediate connections to close the grinding-rolls. Thus it will be seen that the movement of the hand-lever to the right first causes theopening of the feed-gates and afterward closes the rolls to a position for grinding. If with the parts in a grinding position the liand lever is moved to the left, it will first have the effect of closing the feedgates, and thereafter, its stud having in the meantime reached the lower end of the slot, it will cause the grinding-rolls to separate.

The foregoing operation of the parts is in practice of the highest importance, since it prevents the grinding-rolls from being opened at such time as to permit the passage of the unground material accumulated on them, and, on the other hand, prevent the rolls from be ing brought together except at the instant the material is delivered to them. Consequently the mill is free from liability to permit the passage of unground material, and also free from liability of the rolls acting injuriously upon each other.

Referring to the mill represented in Fig. 2, A represents the frame; B,thc stationary rolls; (J, the movable rolls, and D upright arms in which the movable rolls are mounted. These arms are pivoted at the lower end and the two arms which sustain each roll connected by rods E to eccentrics F and a transverse rockshaft, G, there being one of these shafts for each movable roll. The rock-shafts are provided with crank arms H and connected by a cross-bar, 0, engaging studs on the arms. This bar is slotted for the passage of the studs, so that it may play endwise to a limited extent without imparting motion to the arm or roll spreading devices. the machine is provided with vertically-sliding feed-controlling gates of ordinary form, and two horizontal feed-rolls are arranged below the gates and above the grinding-rolls, as usual. Each gate is operated by a rockshaft, P, mounted within the hopper and provided with a projection which engages between studs or shoulders on the gate. The rock-shafts P are provided with depending arms m, connected by rods n to a cross-bar or double crank, cl, mounted centrally on a stud, e, on the frame or hopper. The parts thus arranged cause the two gates to open or close simultaneously.

By the side of the lever 11, and on the same journal therewith, is an arm, 1), the lower end of which bears between two studs, q, on the side of the roll-spreading bar 0. The arm 1) has a frictional connection with the lever d, the two parts being arranged to bear directly against each other or against an intervening washer of elastic material. This washer may be applied in a flat form, as shown in Fig. 7; or, if it be omitted, the two parts 0 androf the parts (i and J may be made concave and con vex, as shown in Fig. 6, to produce the required degree of friction between them.

Assuming the parts to stand in the position shown in Fig. 2, with the feed-gates open and the grinding-rolls closed,the movement of the barO to the left will first have the effect of operating the arm 12, and through the intermediate parts of closing the feed-gates. During the closing action of the gates the arms H are permitted to remain at, rest by reason of the slotted connection between them and the arm 0; but at or about the time that the closing action of the gates is completed the ends of the slots in the bar strike the studs on the crank-arms H, thereby separating the rolls. A reverse movement of the bar O-that is, a movement to the rightwill have the effect of first opening the gates and subsequently closing the rolls.

In Fig. 4 I have represented a mill containing a single pair of grinding-rolls with a rotary feed-gate connecting two roll-spreading devices in form and arrangement identical with those represented in Fig. 1, the sameletters indicating like parts in the two figures, and the parts shown in Fig. 4. operating in the same manner and with the same effect as the corresponding parts in the first figure.

It is to be noted that my improvements may be applied in connection with gates and gateadjusting devices of any approved form.

In Fig. 8 I have illustrated a sliding gate provided with a rack and operated by a' pinionor rock-shaft. This construction may be The double hopper K on the top of substituted in place ofthat represented in the previous figures.

I am aware that mechanism for adjusting a grinding-roll has been combined through intermediate devices with a mechanism for adjusting a feedgate, the spreading of the rolls occurring simultaneously with the closing of the gate, and vice versa, and to such construction I lay no claim.

I do not claim herein the combination of a rollspreading mechanism and a feed-roll-driving mechanism to cause the stoppage of the feeding and grinding actions successively, the same being described and claimed in my ap plication for Letters Patent No. 135,793, filed June 28, 188i; nor do I claim herein the specific form of gate-controlling and roll-spreading mechanism shown in my application for patent, No. 138,781, filed July 25, 1884.

It will he observed that in each embodiment of my invention, as herein represented, the rol1-spreading and the gateoperating mech' anisms are connected by a motion-retarding devicethat is to say, a device which causes said mechanisms to operate successively instead of simultaneously.

Having thus described my invention, what I claim is- 1. In a grimliug-mill, the combination ofa hopper, a t'eedcontrolling gate, two grindingrolls, one of which is movable, roll and gate adjusting mechanisms, an operating-lever, a device permitting a loose sliding connection with the roll adjusting mechanism, and africtioucoupling with a gate-adjusting mechanram.

2. In a grimliuginill, the combination of the grinding-rolls,a roll-spreading mechanism, and a hand-lever to operate the spreading mechanism, with a fecdcontrolling gate, a stop to limit the motion of the gate, gate-operating mechanism, and a frictional connect-ion between the gateoperating mechanism and the lever.

In a roller grinding-mill, the combination of a hopper, a feed-controlling gate and its operating mechanism, a stationary grinding-roll, B, a movable grindingroll, O, a bar, I, intermediate devices between said bar and the movable roll, the hand-lever ,I, connected to the bar I and having a limited movement independent thereof, and a friction-coupling connecting the feed-controlling gate and the gate operating devices with lever J, substantially as described.

at. In a roller grinding-mill, the combination of the grinding-rolls, a roll-spreading mechanism, as usual, a feed controlling gate, and gate-operating mechanism, as usual, and an intermediate motion-rctarding device connecting said mechanisms, as described, in such relation that they are caused to operate successivel y instead of simnltaneousl y.

5. In a roller grinding-mill, the combination of the rollspreading mechanism, a feedcontrolling gate and its operating mechanism, and a motionretarding device connecting said mechanisms in position to cause the closing of the gate and spreading of the rolls in the order named.

\VILLIAM D. GRAY.

Witnesses:

RICHARD HOPIIN, RICHARD BIRKHOLZ. 

